The present invention relates to a disturbance detection and recording system for detecting and recording disturbances, e.g., transients, in periodic signals. The system includes a delay memory for sampled digital signal values of the periodic signal and circuitry for the mutual comparison of successive signal periods as well as at least one disturbance-controlled start selector which supplies a starting pulse to an output device for, for example, recording the delayed signal values.
Such a system is described in the article "Delay Unit OSCILLOSTORE for the Detection of Trouble Values" in Siemens-Zeitschrift 45 (1971), no. 10, pages 634 and 635. From the data in the heading enttiled "Technical Data of a Six-Channel Design" of the article, it can be seen that the "on" duration of the recording equipment is 1 to 10 seconds. This "on" time begins with a starting signal for a high speed recorder serving as the output unit, which is delivered by a start selector, for instance, a du/dt stimulus. The "on" time is independent of the duration of the interface signal which is to be recorded. The "on" time can optionally be fixed in accordance with experience values. However, it can be expected that the actual duration of an interference signal frequently exceeds or falls short of the set "on" time, so that either valuable information is lost, and in the other case, recording material is additionally spent for normal conditions of no interest.
In an article "Automatic Evaluation of Magnetic Tape Recordings with the OSILLOSTORE" from Siemens Zeitschrift 47 (1973), no. 12, pages 869 to 872, it is explained under the heading "Conventional Measuring Techniques-Programmed Measurement", that, as soon as the measurement data show an undisturbed pattern again, the discriminators provided for detecting the interference or trouble turn the output device off again. While this method prevents the situation where data of a disturbance of interest are not recorded because of too short an "on" time, it does not prevent the recording of unimportant data of an interference which has become stationary, and thereby, waste of recording material.